Clamping device for axially tightening a tool, in particular a disc

ABSTRACT

The clamping device for portable grinding machines is part of the clamping nut, which can be screwed on the threaded spindle portion of the drive spindle (10) at its free end for tightening a grinding disk. The clamping nut carries a non-rotatable and axially displaceable clamping disk. Both contain annular surfaces (25, 26) which complement one another approximately so as to form a ball groove, and balls serving to support the clamping disk can roll along these annular surfaces. The clamping disk and clamping nut are coupled via coaxial longitudinal pins which simultaneously form ball stops. A ring with a ball groove sits axially between the clamping disk (21) and the clamping nut, and radial pins projecting into the ball track press against the balls via springs. The annular surface of the clamping disk contains ball cut-out portions, the balls penetrating into the ball cut-out portions when the actuating member is rotated accompanied by axial relieving of the clamping disk (FIG. 1).

BACKGROUND OF THE INVENTION

1. Prior Art

My invention relates to a clamping device or chuck for axially clampinga tool, especially a disk.

A clamping device for clamping a tool to a flange on a driven spindle isknown comprising a clamping nut, which can be screwed on a threadedspindle portion of the spindle on its free end, and a clamping diskwhich is arranged axially between the tool and the clamping nut, issupported at the clamping nut and can press against the tool and pressthe latter against the flange. Such clamping devices are chieflysuitable for portable hand-held machine tools and particularly forgrinding machines. A clamping device of the aforementioned type is known(DE-PS 30 12 836) in which the clamping disk consists of an elementwhich is approximately hat-shaped in cross section and is supportedaxially against the flange of the clamping nut via a helical spring. Inscrewing on and tightening the clamping nut, this clamping disk ispressed axially against the tool via the axially compressed spring, andthe tool is accordingly tightened against the flange on the spindleside. The front side of a cylindrical shoulder of the clamping nut comesinto immediate contact at a facing axial side of the flange on thespindle side and, if the clamping nut is tightened further, the flangeon the spindle side is tightened together with the clamping nut,possibly until the rear flange comes into contact axially at theshoulder surface of the spindle forming the supporting element. It is tobe achieved by means of this, in an angle grinder, that the grindingdisk is clamped with defined contact pressing pressure and that thiscontact pressing pressure is ensured. This clamping device is alsosupposed to make it possible to exchange the grinding disk quickly andsimply and simultaneously to prevent an overloading of the hand-heldmachine tool, particularly the angle grinder. That is, if the torqueacting on the grinding disk is too great, the grinding disk stops, whilethe rear flange and the clamping nut, with the clamping disk, execute arelative movement thereto. This clamping device counters the effectwhereby the clamping nut continues to tighten by itself duringoperation, which would otherwise considerably impede the loosening ofthe clamping nut when changing the grinding disk. Nevertheless, it isonly possible to loosen the clamping nut with the use of a specialauxiliary tool, wherein the spindle must be held reciprocally by meansof a second auxiliary tool, e.g. a wrench, depending on the design ofthe machine.

SUMMARY OF THE INVENTION

Accordingly, it is an object of my invention to provide an improvedclamping device for axially clamping a tool which may be loosened in aquick and reliable manner for exchange of tools.

It is also an object of my invention to provide an improved clampingdevice for axially clamping a tool which may be converted withoutspecial rebuilding.

In keeping with these objects and with other which will become apparenthereinafter, the clamping disk is coupled with the clamping nut so as tobe axially displaceable but fixed with respect to rotation relative toit and is axially supported by a plurality of rolling bodies guided ontracks of the clamping disk and the clamping nut. An actuating memberacting on the rolling bodies is arranged between the clamping disk andthe clamping nut and presses the rolling bodies against stops of theclamping disk in one direction corresponding to the tightening directionand in the opposite direction moves them along the tracks until atrespectively assigned axial and/or radial cut out portions which openinto the tracks thus relieving the clamping disk from clamping pressure.

There are several possible embodiments of my invention. Advantageouslythere are three rolling bodies distributed equidistant circumferentiallyand the rolling bodies are balls. The actuating member may consist of aring which is arranged axially between the clamping disk and theclamping nut and is held so as to be rotatable relative thereto and thering comprises an inner track assigned to the rolling bodies. The tracksmay be formed from annular surfaces on the clamping disk, on theclamping nut and on the actuating member having the shape of acircular-arc portion in cross section and adapted to the ball radius ofthe balls. Together the clamping disk, the clamping nut and theactuating member form a guide groove for the balls in which the ballscan roll in the circumferential direction during relative rotationbetween the actuating member and the clamping disk with the clampingnut.

In the clamping device, according to the invention, with thecharacterizing features of the main claim, the following advantagesresult. It is possible to exchange tools without any auxiliary tool, andthis can be done in a quick and secure manner. Another advantageconsists in that already existing hand-held machine tools can also beconverted without special rebuilding. For this purpose, a simpleexchange of the existing conventional clamping nut with a completingunit is sufficient, which completing unit comprises a clamping nut withclamping disk and actuating member. In all respects, the clamping nutcan be constructed, as before, in a conventional manner, e.g. so as toconform to standards, in the area which is accessible from the outside,so that a wrench can still be applied in particularly tenacious cases,e.g. when the clamping nut is rusted tight, and the clamping nut can beloosened with this auxiliary tool. The same principle used in theclamping device according to the invention can also be used at the rearflange on the spindle side. This flange is then exchanged with thecompleting unit, which comprises clamping nut with clamping disk andactuating member. The clamping disk is then pressed against the tool atthe rear. As directly equivalent to the structure described the mainclaim, this exchange is likewise to be comprised by that. Advantageousdevelopments and improvements of the clamping device indicated in themain claim are made possible by means of the features indicated in thesubclaims.

The complete wording of the claims is not repeated in the following onlyin order to avoid unnecessary repetition. However, all these features ofthe claims are to considered as disclosed in this place expressly and assubstantial to the invention. All features mentioned in this descriptionand all features which are discernable from the drawing alone areadditional component parts of the invention, even if they are notparticularly emphasized and not mentioned in the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

An embodiment example of the invention is shown in the drawing andexplained in more detail in the following description.

FIG. 1 is a schematic cross sectional view of a clamping deviceaccording to my invention which is part of an angle grinder with clampedin grinding disk;

FIGS. 2 and 3 are schematic cross sectional views taken along linesII--II and III--III in FIG. 1.

DETAILED DESCRIPTION OF THE INVENTION

The drawings show the lower part of a portable hand-held machine toolwhich is constructed e.g. as an angle grinder, and which comprises aspindle 10 which is driven by means of a motor and via a gear unit. Thespindle 10 continues in a cylindrical portion 12 of smaller diameter atan annular shoulder 11 and then into a threaded spindle portion at thefree end of the spindle. The threaded spindle portion comprises anexternal thread 14. The spindle 10 serves to drive a tool 15 whichcomprises e.g. the indicated grinding disk or another tool disk, arubber plate, or the like. The tool 15 is clamped and tightened betweena flange 16 and a clamping member which is part of clamping nut 17 andis explained in more detail in the following. The flange 16 is supportedaxially at the annular shoulder 11 and is centered radially on thecylindrical portion 12. The flange 16 engages with the spindle 10 in apositive-locking manner so as to be fixed with respect to rotationrelative to it by means of shaped surfaces at the spindle 10 and theflange 16, which shaped surfaces, e.g. two flattened portions which areparallel to one another, fit together, the flange 16 being carried alongby the spindle 10 in the circumferential direction according to arrow 9when the motor is switched on so as to be fixed with respect to rotationrelative to it. This circumferential direction, according to arrow 9,corresponds to the working direction of the tool 15 in which the latteris driven. In the top view according to FIG. 2, this corresponds to theclockwise direction. The clamping nut 17 comprises a flange 18 and acylindrical-sleeve-shaped hub 19 proceeding from the latter and isprovided with a continuous internal thread 20 in the hub 19, theclamping nut 17 being screwed onto the external thread 14 of thethreaded spindle portion 13 by means of this internal thread 20. Thetool 15 is centered on the outer circumferential surface of the hub 19when fastening.

A clamping disk 21, which comprises a clamping plate 22 pressing againstthe tool 15 and a supporting hub 23, is arranged in the axial areabetween the tool 15 and the clamping nut 17. The clamping disk 21 can beacted upon by axially directed pressing force proceeding from theclamping nut 17 and is capable of pressing axially against the tool 15and pressing the latter securely against the axial front side of theflange 16.

The clamping disk 21 is coupled with the clamping nut 17 so as to beaxially displaceable but non-rotatable relative to it and is axiallysupported by means of rolling bodies 24. In the shown embodiment, thereare three rolling bodies 24 which are arranged so as to be spacedapproximately equidistant circumferentially and are constructed here asballs. These balls 24 are guided on tracks of the clamping disk 21 andof the clamping nut 17 which are concentric relative to the centralaxis, these tracks are formed in each instance from annular surfaces 25,26 of the clamping disk 21 and clamping nut 17, respectively, whichannular surfaces 25, 26 are shaped in the manner of a circular-arcportion in cross section and extend axially at a distance from oneanother and, in so doing, have identical radii and are adapted to thespherical radius of the balls 24. The clamping disk 21 is centered withthe continuous inner circumferential surface 27 of the hub 23 and of theclamping plate 22 on the outer circumferential surface of the hub 19 andare held and guided so as to be axially movable, at least within limits.

An actuating member 28 in the form of a ring 29 is arranged between theclamping disk 21 and the clamping nut 17 and overlaps the clamping plate22 in the axial direction with an upper annular collar 30 in FIG. 1while leaving clearance for movement by it. The annular collar 30 endsaxially at a distance from and, according to FIG. 1, below the end faceof the clamping plate 22 contacting the tool 15. The actuating member 28acts on the balls 24, pressing the latter against stops 31 of theclamping disk 21 in the direction corresponding to the tighteningdirection, opposite the direction of arrow 9. This clamping state isshown in FIGS. 1 -3.

The ring 29 sits axially with clearance of for movement between theclamping disk 21 and the clamping nut 17 and is held so as to berotatable relative to both. In its interior, the ring 29 contains anannular surface 32 which is assigned and adapted to the balls 24, isapproximately groove-shaped in cross section, and serves as a track forthe balls 24, the latter being in contact with the track. This annularsurface 32, together with the other annular surfaces 25, 26 of theclamping disk 21 and clamping nut 17, respectively, forms a guide groovefor the balls 24 which is adapted to the diameter of the balls 24 and inwhich the balls 24 can roll in both rotating directions in thecircumferential direction during relative rotation between the ring 29on the one hand and the clamping nut 17 with clamping disk 21 on theother hand, the clamping disk 21 being attached at the clamping nut 17so as to be fixed with respect to rotation relative to it.

As can be seen from FIG. 3 alone, a cut out portion 33, which isassigned to the ball 24, is contained in the area of the annular surface25 of the clamping disk 21 for every ball 24, which cut out portion 33consists in each instance of a recess in this annular surface 25 and isconstructed e.g. as a ball pocket which is recessed at least axially atthe top in FIG. 1 and opens in the opposite direction of the latter; theball pocket can also open radially, in addition, and opens into theadjacent area of the annular surface 25 in each instance. Every cut outportion 33 is fashioned such that the balls can penetrate deeper axiallyin the area of the annular surface 25 of the clamping disk 21 during therolling of the balls 24 and when the respective assigned cut out portion33 is reached, so that the axial distance between the clamping disk 21and the clamping nut 17 is at least slightly reduced, and accordinglythe clamping disk 21 is relieved of clamping pressure.

The actuating member 28 is provided, per ball 24, with a fixed driver 34in the form of a radial pin 35 which is securely attached at the ring 29and projects radially from the outside to the inside into the track ofthe respective ball 24 situated in the front at least far enough so thate.g. an approximately tangential contact is effected at the respectiveball 24 situated in the front.

The stops 31 of the clamping disk 21 are formed from approximatelycoaxial longitudinal pins 36 which are securely arranged at the clampingdisk 21 and extend up to bore holes 37 in the clamping nut 17 in whichthey engage e.g. with sliding clearance. In so doing, the longitudinalpins 36 engage approximately coaxially through the guide groove for theballs 24, which is formed by the annular surfaces 25, 26 and 32 togetherand in such that there is still sufficient intermediate space betweenthe inner surface of the ring 29 and the longitudinal pins 36, so thatthe latter do not rub against the actuating member 28 in an abrasivemanner during the relative rotation between the actuating member 28 onthe one hand and the clamping nut 17, with the clamping disk 21, on theother hand. Because of this design, the longitudinal pins 36 areconstructed simultaneously for the positive-locking connection of theclamping disk 21 with the clamping nut 17 in the circumferentialdirection. The stops 31 in the form of these longitudinal pins 36 arelocated in each instance on the other side of the respective assignedball 24, which side is located opposite the radial pin 35 for every ball24. In the clamping position shown in FIGS. 1-3, with the tool 15tightened and the motor turned on, the clamping disk 21 is also carriedalong in the working direction according to arrow 9 via the clampingforce and friction, as is clamping nut 17 via the longitudinal pins 36.

In so doing, the longitudinal pins 36 abut in the direction of arrow 9at the respective balls 24 which are situated in front and which pressagainst the respective radial pins 35 of the actuating member 28 whichare situated in front. The actuating member 28 is spring-loaded in theopposite direction of the circumferential direction according to arrow9, which simultaneously corresponds to the loosening direction. This isachieved by means of respective cylindrical helical springs 38 which areplaced inside the guide groove formed by the annular surfaces 25, 26 and32 and act in the circumferential direction. Every helical spring 38 isarranged in the circumferential area between a longitudinal pin 36 and aradial pin 35 and is supported at the latter on the end side. Theactuating member 28 is acted upon in a resiliently elastic manner bymeans of these helical springs 38 relative to the clamping nut 17 withclamping disk 21 in the opposite direction of arrow 9 in such a way thatthe respective radial pin 35 presses the ball 24 situated in front,respectively, in the direction opposite the arrow 9 against thelongitudinal pin 36 situated in front. The actuating member 28 isaccordingly held via the helical springs 38 in the clamping positionshown in FIGS. 1-3 relative to the clamping nut 17 with clamping disk21.

The clamping disk 21 is secured at the clamping nut 17 while allowing atleast slight axial movement. A spring ring 39 is used for this purpose,which spring ring 39 is received in a groove 40 on the outercircumferential surface of the hub 19 of the clamping nut 17 in asubstantially accurate fit, specifically in such a way that the springring 39 penetrates into the groove 40 e.g. with half its cross section,while the other half of its cross section projects up radially. Theclamping disk 21 contains, on the inner circumferential surface 27 ofthe hub 23, a groove 41 which is assigned to the spring ring 39;however, the groove 41 has a greater axial width than the spring ring 39and the groove 40. The radially measured depth of the groove 41corresponds approximately to the other half of the cross section of thespring ring 39. It is not shown in detailed in the drawings but theflanks of the groove 40 and/or 41 can be beveled so as to enable aslight sliding together and subsequent loosening of the clamping disk 21and clamping nut 17 in the axial direction.

Sealing elements e.g. foam-rubber rings, which are not shown in moredetail, can be arranged in the intermediate spaces between the ring 29and the clamping disk 21 on one of the axial sides of the ring 29 andbetween the ring 29 and the flange 18 of the clamping nut 17 on itsother axial side. These sealing elements ensure a sealing against thepenetration of dirt, e.g. grinding dust, or the like. The sealingelements are inserted during assembly.

FIGS. 1-3 show the described clamping device in the clamping position inwhich the tool 15 is tightened axially at the flange 16 via the clampingdisk 21, axially supported via the balls 24 at the clamping nut 17.

If the tool 15 is removed and exchanged, the flange 16 and/or the tool15 is blocked with respect to rotation via suitable means; this can beeffected e.g. by means of a spindle locking device integrated in thehand-held machine tool. Under certain circumstances, the friction in thegear possibly also hinders the spindle 10 from rotating in the directionof the arrow 9, at least within limits. To loosen, the actuating member28 is then rotated by hand in the working direction according to arrow9, wherein the radial pins 35 are moved from the balls 24 and,accompanied by compression of the helical springs 38, moved in thecircumferential direction in the direction of the longitudinal pins 36of the clamping disk 21 with clamping nut 17, the clamping disk 21 doesnot rotate relative to it. During this movement, the balls 24 roll onthe tracks formed by means of the annular surfaces 25, 26 and 32,wherein the balls 24 likewise migrate in the circumferential directionaccording to arrow 9. As soon as the balls 24 have reached the cut outportions 33 in the annular surface 25 of the clamping disk 21 duringthis movement, the balls 24 penetrate axially into these cut outportions 33. In this position, the clamping disk 21 can deflect axiallyrelative to the clamping pressure, i.e., in the view of FIG. 1, axiallyat least slightly in the direction of the clamping nut 17, and candisplace the ring 29 at least far enough so that a corresponding axialrelieving can be achieved. Thereupon, the completing unit, consisting ofclamping nut 17 with clamping disk 21 and actuating member 28, caneasily be completely screwed off by hand. The relative swivelingmovement of the actuating member 28 for relieving the clamping disk 21axially is limited in that the radial pins 35 abut at the longitudinalpins 36 when the helical springs 38 are entirely compressed. As soon asthe axial relieving is effected and the completing unit can easily becompletely screwed off by hand, the repositioning of the balls 24 iseffected automatically because of the relaxing helical springs 38. Theactuating member 28 is turned back again, relative to the clamping nut17 with clamping disk 21, into the initial position shown in FIGS. 1-3by means of the spring pressure on the radial pins 35, wherein, by meansof the rolling movement of the balls 24, the balls 24 are moved out ofthe cut out portions 33 again and moved back into the shown position. Inthis position, the completing unit, consisting of clamping nut 17 withclamping disk 21 and actuating member 28, is ready for tightening a newinserted tool. For this purpose, it is sufficient to tighten thiscompleting unit slightly opposite the direction of arrow 9 when screwingon the threaded spindle portion and accordingly slightly tightening thenew tool 15, since the tool 15 tightens by itself in operation when themotor is subsequently switched on.

Thanks to the balls 24 the friction effected during the relativerotation of clamping disk 21 between the actuating member 28 and theclamping nut 17, is a rolling friction which is accordingly practicallynegligibly small.

The described clamping device is simple, inexpensive and quick, secureand easy to handle. It makes it possible to exchange the tool 10 rapidlyand securely without requiring additional special tools for thispurpose. Another advantage consists in that already existing hand-heldmachine tools, particularly grinding machines, can also be equipped withthis clamping device subsequently without special rebuilding. For thispurpose, its conventional clamping nut need only be replaced by thecompleting unit consisting of clamping nut 17 with clamping disk 21 andactuating member 28. Moreover, the clamping nut 17 can be constructed insuch a way that it also enables, if necessary, the application of aspecial tool, e.g. in the form of a two-hole nut wrench, as was possiblepreviously, so that the clamping nut 17 and, accordingly, the entirecompleting unit can also still be loosened in a conventional manner bymeans of such an auxiliary tool in particularly tenacious cases, e.g. inthe rusted state. The clamping device is not limited to a grinding diskas tool 15. On the contrary, such tools as clamping disks, brushes,rubber plates, and the like, can also be clamped in the same mannerwithout the use of tools.

It will be understood that each of the elements described above, or twoor more together, may also find a useful application in other types ofstructures differing from the types described above.

While the invention has been illustrated and described as embodied in aclamping device for axially clamping a tool, it is not intended to belimited to the details shown, since various modifications and structuralchanges may be made without departing in any way from the spirit of thepresent invention.

Without further analysis, the foregoing will so fully reveal the gist ofthe present invention that others can, by applying current knowledge,readily adapt it for various applications without omitting featuresthat, from the standpoint of the prior art, fairy constitute essentialcharacteristics of the generic or specific aspects of this invention.

What is claimed as new and desired to be protected by Letters Patent isset forth in the appended claims.
 1. In a clamping device for clamping atool, especially a disk, to a flange on a driven spindle having athreaded spindle portion at a free end thereof, comprising a clampingnut, which is screwable on said threaded spindle portion, and a clampingdisk, which is arranged axially between said tool and said clamping nut,is supported on said clamping nut and is pressible against said tool topress said tool against said flange, the improvement wherein saidclamping disk has a plurality of stops and is coupled with said clampingnut so as to be axially displaceable but fixable with respect torotation relative to said clamping nut and has a plurality ofcircumferential tracks and a plurality of cut out portions which openinto said tracks, and said clamping device further comprises a pluralityof rolling bodies guided on said tracks of said clamping disk and saidclamping nut to support said clamping disk axially and an actuatingmember arranged between said clamping disk and said clamping nut whichacts on said rolling bodies and presses said rolling bodies against saidstops of said clamping disk in one circumferential directioncorresponding to a tightening direction and moves said rolling bodies inan opposite circumferential direction along said tracks until atassigned ones of said cut out portions which open into said tracks torelieve said clamping disk from clamping pressure.
 2. The improvementaccording to claim 1, wherein three of said rolling bodies are providedand are arranged so as to be approximately equidistantcircumferentially.
 3. The improvement according to claim 1, wherein eachof said rolling bodies is a ball.
 4. The improvement according to claim1, wherein said actuating member includes a ring which is arrangedaxially between said clamping disk and said clamping nut and is held soas to be rotatable, and said ring comprises an inner track assigned tosaid rolling bodies which contact on said track.
 5. The improvementaccording to claim 3, wherein said tracks are formed from a plurality ofannular surfaces in said clamping disk, in said clamping nut and in saidactuating member, said annular surfaces having a circular-arc portion incross section adapted to fit said balls to that, together, said clampingdisk, said clamping nut and said actuating member form a guide groovefor said balls, in which said balls can roll in one of saidcircumferential direction during relative rotation between saidactuating member and said clamping disk with said clamping nut.
 6. Theimprovement according to claim 1, wherein said clamping disk has anannular surface and said cut out portions are provided as recesses insaid annular surface.
 7. The improvement according to claim 6, whereinsaid rolling bodies comprise balls and said recesses are structured asaxial ball pockets which open radially exteriorly and in which saidballs can deflect during rolling as a result of rotation of saidactuating member in said circumferential direction so that said clampingdisk is relieved and loosened to provide axial displacement of saidclamping disk.
 8. A clamping device for clamping a tool, especially adisk, to a flange on a driven spindle having a threaded spindle portionat a free end thereof, comprising a clamping nut, which is screwable onsaid threaded spindle portion, and a clamping disk, which is arrangedaxially between said tool and said clamping nut, is supported on saidclamping nut and is pressible against said tool to press said toolagainst said flange, said clamping disk having a plurality of stops andbeing coupled with said clamping nut so as to be axially displaceablebut fixable with respect to rotation relative to said clamping nut, andsaid clamping disk and said clamping nut also having a plurality ofcircumferential tracks, and a plurality of cut out portions which openinto said tracks are provided, and further comprising a plurality ofrolling bodies guided on said tracks of said clamping disk and saidclamping nut to support said clamping disk axially and an actuatingmember arranged between said clamping disk and said clamping nut whichacts on said rolling bodies and presses said rolling bodies against saidstops of said clamping disk in one circumferential directioncorresponding to a tightening direction and moves said rolling bodies inan opposite circumferential direction along said tracks until atassigned ones of said cut out portions which open into said tracks torelieve said clamping disk from clamping pressure, and wherein saidactuating member is spring-loaded in said circumferential directionopposite to said one of said circumferential directions in which saidactuating member is rotated to provide relief of said clamping disk. 9.The improvement according to claim 1, wherein said actuating membercomprises a stationary driver for each of said rolling bodies, saidstationary driver projecting into said track of said rolling body andabutting on said rolling body in one direction.
 10. The improvementaccording to claim 1, wherein said clamping disk comprises one of saidstops which penetrates said track transversely for each of said rollingbodies, said rolling body abutting on said stop in one of saidcircumferential directions.
 11. A clamping device for clamping a tool,especially a disk, to a flange on a driven spindle having a threadedspindle portion at a free end thereof, comprising a clamping nut, whichis screwable on said threaded spindle portion, and a clamping disk,which is arranged axially between said tool and said clamping nut, issupported on said clamping nut and is pressible against said tool topress said tool against said flange, said clamping disk having aplurality of stops and being coupled with said clamping nut so as to beaxially displaceable but fixable with respect to rotation relative tosaid clamping nut, and said clamping disk and said clamping nut alsohaving a plurality of circumferential tracks, and a plurality of cut outportions which open into said tracks are provided, and furthercomprising a plurality of rolling bodies guided on said tracks of saidclamping disk and said clamping nut to support said clamping diskaxially and an actuating member arranged between said clamping disk andsaid clamping nut which acts on said rolling bodies and presses saidrolling bodies against said stops of said clamping disk in onecircumferential direction corresponding to a tightening direction andmoves said rolling bodies in an opposite circumferential direction alongsaid tracks until at assigned ones of said cut out portions which openinto said tracks to relieve said clamping disk from clamping pressure,said actuating member comprising a stationary driver for each of saidrolling bodies, said stationary driver projecting into said track ofsaid rolling body and abutting on said rolling body in one direction,and wherein said driver is formed as a radial pin.
 12. A clamping devicefor clamping a tool, especially a disk, to a flange on a driven spindlehaving a threaded spindle portion at a free end thereof, comprising aclamping nut, which is screwable on said threaded spindle portion, and aclamping disk, which is arranged axially between said tool and clampingnut, is supported on said clamping nut and is pressible against saidtool to press said tool against said flange, said clamping disk having aplurality of stops and being coupled with said clamping nut so as to beaxially displaceable but fixable with respect to rotation relative tosaid clamping nut and said clamping disk and said clamping nut alsohaving a plurality of circumferential tracks, and a plurality of cut outportions which open into said tracks are provided, and furthercomprising a plurality of rolling bodies guided on said tracks of saidclamping disk and said clamping nut to support said clamping diskaxially and an actuating member arranged between said clamping disk andsaid clamping nut which acts on said rolling bodies and presses saidrolling bodies against said stops of said clamping disk in onecircumferential direction corresponding to a tightening direction andmoves said rolling bodies in an opposite circumferential direction alongsaid tracks until at assigned ones of said cut out portions which openinto said tracks to relieve said clamping disk from clamping pressure,said actuating member comprising a stationary driver for each of saidrolling bodies, said stationary driver projecting into said track ofsaid rolling body and abutting on said rolling body in one direction,and further comprising a spring arranged in one circumferential area, asview in one of said circumferential directions corresponding to saidtightening direction, between one of said stops and one of said driversand supported by both said stop and said driver and actscircumferentially, said actuating member being acted upon in saidcircumferential direction by said spring relative to said clamping nutand said clamping disk so that said driver presses said rolling bodiesagainst said stop, said rolling body being positioned between saidspring and said stop.
 13. The improvement according to claim 12, whereinsaid stop comprises a longitudinal pin and said driver comprises aradial pin.
 14. The improvement according to claim 1, wherein saidclamping disk has an inner circumferential surface and said clamping nuthas a cylindrical-sleeve-shaped hub positionable adjacent said innercircumferential surface, said clamping disk with said innercircumferential surface being centered on said cylindrical-sleeve-shapedhub of said clamping nut and held and guided so as to be axially movableto a limited extend.
 15. A clamping device for clamping a tool,especially a disk, to a flange on a driven spindle having a threadedspindle portion at a free end thereof, comprising a clamping nut, whichis screwable on said threaded spindle portion, and a clamping disk,which is arranged axially between said tool and said clamping nut, issupported on said clamping nut and is pressible against said tool topress said tool against said flange, said clamping disk having aplurality of stops and being coupled with said clamping nut so as to beaxially displaceable but fixable with respect to rotation relative tosaid clamping nut and said clamping disk and said clamping nut alsohaving a plurality of circumferential tracks, and a plurality of cut outportions which open into said tracks are provided, and furthercomprising a plurality of rolling bodies guided on said tracks of saidclamping disk and said clamping nut to support said clamping diskaxially and an actuating member arranged between said clamping disk andsaid clamping nut which acts on said rolling bodies and presses saidrolling bodies against said stops of said clamping disk in onecircumferential direction corresponding to a tightening direction andmoves said rolling bodies in an opposite circumferential direction alongsaid tracks until at assigned ones of said cut out portions which openinto said tracks to relieve said clamping disk from clamping pressure,and wherein said clamping disk has an inner circumferential surface andsaid clamping nut has a cylindrical-sleeve-shaped hub positionableadjacent said inner circumferential surface, said clamping disk withsaid inner circumferential surface being centered on saidcylindrical-sleeve-shaped hub of said clamping nut and held and guidedso as to be axially movable to a limited extent and further comprising aspring ring located in adjacent annular grooves of said clamping nut andsaid clamping disk, said spring ring engaging in one of said grooves ina positive-locking manner, and one of said grooves has an axial widthgreater than that of said spring ring.
 16. The improvement according toclaim 15, wherein said groove receives said spring ring in anapproximately accurate fit and is provided in an outer circumferentialsurface of said hub and another of said grooves having a greater axialwidth is arranged in an inner circumferential surface of said clampingdisk.
 17. The improvement according to claim 11, wherein said stops ofsaid clamping disk are simultaneously structured for positive-lockingconnection of said clamping disk with said clamping nut.
 18. Theimprovement according to claim 17, wherein said stops compriselongitudinal pins.
 19. The improvement according to claim 17, whereinsaid clamping nut is provided with a bore hole and each of said stops isarranged so as to be fixed on said clamping disk and extends up to saidbore hole in said clamping nut in which said stop engages with slidingclearance.
 20. The improvement according to claim 1, wherein each ofsaid cut out portions is an axially-extending portion.
 21. Theimprovement according to claim 1, wherein each of said cut out portionsis a radially-extending portion.